Optolong L-eXtreme FilterDescription Unlike the Optolong L eNhance filter which is a tri band (transmits Hb, Ha, and OIII), the L eXtreme filter is dual band that passes Ha and OIII emission lines. L eXtreme is a two 7nm bandpass filter which can be used with one shot color cameras like DSLR's (digital SLR), and monochrome CCD cameras, it is also more suited for fast systems. The convenience and cost effectiveness of this filter allows amateurs to image a rich emission